The Chicago Cubs saw a need for expanded seating with improved handicap accessibility to accommodate the ever-increasing numbers of Cubs fans.
Project challenges included:
| Blending the historic seating deck with the new cantilevered concourse. |
| Lack of reference drawings. |
| Limited space available to offset the vibrations and deflections of the large cantilevered concourse. |
| Isolation of new framing structure from the existing structure to avoid overloading existing foundations. |
Osborn addressed these challenges by obtaining as-built field information, which enabled them to design a steel-framed structure that seamlessly integrated the existing bleachers. Elevator access to the new upper concourse addressed handicap accessibility issues. Undesirable vibrations and deflections were minimized by stiffening the cantilevered structure. Stiffening was accomplished with the use of knee braces. These knee braces and their associated connections were designed to mimic the as-built structural detailing found in the original structure. As a result, the required stiffening also provided the additional benefit of being able to blend the new structure with the look of the old bleachers.